Electric starting motor for internal combustion engines



Aug. 7, 1934. A. KAUFMANN 1,963,947

ELEOTRIC STARTING MOTOR FOR INTERNAL COMBUSTION ENGINES Filed June 21,-1932 gar/111113 Patented Aug. 7, 1934 ELECTRIC STARTING M O T O R FOR INTERNAL COMBUSTION ENGINES Albert Kaufmann, Zuchwil, Switzerland, assignor I to Switzerland Scintilla Aktiengesellschaft,

Solothurn,

Application June 21, 1932, Serial No. 618,575

Claims.

This invention relates to a starting motor the pinion of which is axially displaceable together with the pinion shaft extending through the entire length of the rotor and connected to the pinion shaft in the direction of rotation, the rotor of which is coupled to the pinion shaft by means of an ever-running clutch and a multi-discs friction clutch and said pinion being moved into en agement in such a way that the main switch of the starter is closed after the pinion has been moved into full engagement. In pinion starting motors of this type a steep thread nut is used for bringing about engagement utilizing the inertia of the shaft and the pinion. The special devices which have to be employed for making possible the engagement if the teeth of the pinion strike against the teeth of the ring of teeth, are complicated. In another type of starting motors the pinion shaft of which does not extend through the entire length of the armature, the engagement of the pinion is effected by a shifting device which displaces the pinion axially on the rotor shaft, said shifting device is disposed on the same side of the armature as the pinion. These starting motors are not favourable from the standpoint of mounting the same into the flywheel housing as they give an overhanging design. Further is the steep thread nut of these starting motors so arranged that they can be used in one direction of rotation only.

According to the present invention these disadvantages are overcome by disposing the steep thread nut which is axially displaceable by means of a shifting device on the side of the armature opposite the pinion, by turning the pinion shaft the pinion means of said steep thread nut, if the teeth of pinion strike against the teeth of the ring of teeth of the fly wheel, so that the engagement of the pinion with the flywheel is rendered possible, by uncoupling after complete engagement of the pinion said steep thread nut which is coupled to the current switch by means of a brake disc clutch, and by closing in the next moment the current switch forv operating the starting motor.

the accompanying drawing a constructional example of the invention is shown. The preferred form of the device is the only embodiment of the invention illustrated and will now be described in detail.

Referring to the drawing Fig. 1 represents a longitudinal section through the starter in the disengaged position of the pinion.

Fig. 2 is a plan partly in section showing the brake disc clutch of the shifting device in the disengaged position. i

1 is the pinion shaft to which is firmly fixed the pinion 2. The pinion shaft 1 is connected to the armature by means of an overrunning clutch 21 and a multi-disc friction clutch 22, these members being disposed on the same side of the armature as the pinion. On the side of the armature opposite the pinion the device for turning the pinion shaft in relation to the ring of teeth on the engine flywheel and the device for displacing the pinion are provided. These devices consist of the following parts. At the end of the pinion shaft 1 a steep thread sleeve 3 is firmly fixed. With this steep thread sleeve 3 the steep thread nut 4 engages which has a brake flange 5 which engages with two brake discs 6 and '7. These two brake discs are pressed against one another by the two springs 25, 26 arranged on the bolts 14. Between the brake disc 7 and the brake flange 5 a thrust bearing 8 is disposed. Pivotably fixed to the brake disc 6 is the pawl 9 arranged in a plane at right angles to this brake disc. 10 is a bolt screwed into the starter housing, having a stop at 11 and two nuts 12 at the end of the bolt, the latter serving in the same way as stop for the pawl 9. The steep thread nut a is connected to the conducting bridge 13 of the starter switch by means of the bolts 14 on which the brake discs 6 and '7 are firmly held by the two springs 25, 26.

Bridge 13 has two contact pieces 15 which make contact with the contacts 16; on the drawing one contact piece and one contact only are shown; in this way the battery current is conducted into the starter. The lever 17 bears against the conducting bridge 13 and the latter against the ion shaft 1 by means of the intermediate bolt 18 which works against the spring 19.

The starting motor is started up by displacing axially by means of the lever 17 the conducting bridge 13 which moves by the same amount pinion shaft and the pinion by means of the bolt 18 as well as the steep thread nut 4 by means of the bolts 14. In case the pinion can slide smooth ly into the ring of teeth, no displacement of steep thread nut 4 in relation to the steep thread sleeve 3 takes place. After the pinion has moved nearly into full engagement the pawl 9 comes in contact with the stop 11 and is turned into the position shown in Fig. 2. The brake flange 5 is disengaged from the two brake discs 6 and '7 thereby being capable of turning freely between the two brake discs 6 and '7. Practically in the same moment the conducting bridge 13 makes contact with the contacts 16 and the electromotor starts to turn. After the engine has been started on its own power and the pinion shaft is moved backwards under the action of the spring 23, the two brake discs remain in the disengaged position shown in Fig. 2. As soon as the pawl comes in touch with the nuts 12, it returns into the position shown in Fig. 1. The brake flange 4 of the nut 5 is again held stationary and the rotor of the starting motor thereby brought to a stan still in a short time. The nuts 12 can be adjusted so that the position according to Fig. 1 is attained after the pinion has completely moved out of engagement with the ring of teeth. In case the teeth of the pinion strike against the teeth of the ring of teeth, the pinion shaft cannot move axially any further, but the steep thread nut i is displaced axially and by means of the steep thread connection between the nut 4 and the sleeve 3 a slight rotary movement is imparted to the latter and consequently to the pinion shaft and the pinion itself. When the teeth of the pinion come opposite the gaps between the teeth of the engine flywheel, the pinion can slide into the ring of teeth. The furtheroperations are repeated as described above.

This new starting motor allows a very suitable mounting into the engine and reduces to a minimum the wear of the teeth of the pinion and the ring of teeth of the flywheel; it can be used for any direction of rotation by turning the roller race through 180 as the case may be.

What I claim is:

1. In an electric starting motor in combination an armature shaft, a pinion shaft, a pinion, an overrunning clutch, said pinion shaft extending through the entire length of said armature shaft, a steep thread nut disposed on the side of the armature opposite the pinion, a steep thread sleeve fixed to the pinion shaft and being in thread connection with said steep thread nut, a shifting de-- vice for displacing said pinion shaft, a current switch, a spring loaded lever actuating upon said current switch, a brake disc clutch, said current switch resiliently coupled to said steep thread nut by means of said brake disc clutch.

2. In an electric starting motor in combination an armature shaft, a pinion shaft, a pinion, an overrunning clutch, said pinion shaft extending through the entire length of said armature shaft, a steep thread nut disposed on the side of the armature opposite the pinion, a steep thread sleeve fixed to the pinion shaft and being in thread connection with said steep thread nut, a shifting device for displacing said pinion shaft, a current switch, a spring loaded lever actuating upon said current switch, a brake flange integral with the steep thread sleeve, two brake discs, said brake flange arranged between said two brake discs which are displaceable axially only, said current switch resiliently coupled to said steep thread nut by means of said brake discs.

3. In an electric starting motor in combination an armature shaft, a pinion shaft, a pinion, an-

overrunning clutch, said pinion shaft extending through the entire length of said armature shaft, a steep thread nut disposed on the side of the armature opposite the pinion, a steep thread sleeve fixed to the pinion shaft and being in thread connection with said steep thread nut, a shifting device for displacing said pinion shaft, a current switch, a spring loaded lever actuating upon said current switch, a brake flange integral with said steep thread sleeve, two brake discs, said brake flange arranged between said two brake discs which are displaceable axially only, bolts fixed to said current switch, said two brake discs slidably arranged on said bolts, springs disposed on opposite sides of said'brake discs, said springs adapted to press said brake discs against said brake flange of the steep thread nut.

' 4. In an electric starting motor in combination an armature shaft, a pinion shaft, a pinion, an overrunning clutch, said pinion shaft extending through the entire length of said armature shaft, a steep thread nut disposed on the side of the armature opposite the pinion, a steep thread sleeve fixed to the pinion shaft and being in thread connection with said steep thread nut, a

shifting device for displacing said pinion shaft,.

a current switch, a spring loaded lever actuating upon said current switch, a brake flange integral with said steep thread sleeve, two brake discs, said brake flange arranged between said two brake discs which are displaceable axially only, bolts fixed to said current switch, said two brake discs slidably arranged on said bolts, springs disposed on opposite sides of said brake discs, said springs adapted to press said brake discs against said brake flange of the steep thread nut, a pawl pivotably fixed to one of the two brake discs and between same, stationary stops, an arm and a nose both integral with that pawl, said arm adapted to strike against said stops in the two end positions of the pinion shaft thereby turning said nose of the pawl into such a position that the brake is opened or closed.

5. In an electric starting motor in combination an armature shaft, a pinion shaft, a pinion, an overrunning clutch, said pinion shaft extending through the entire length of said armature shaft, a steep thread nut disposed on the side of the armature opposite the pinion, a steep thread sleeve fixed to the pinion shaft and being in thread connection with said steep thread nut, a shifting device for displacing said pinion shaft, a current switch, a spring loaded lever actuating said current switch, a brake flange integral with said steep thread sleeve, two brake discs, said brake flange arranged between said two brake discs which are displaceable axially only, bolts fixed to said current switch, said two brake discs slidably arranged on said bolts, springs disposed on opposite sides of said brake discs on said bolts adapted to press said brake discs against said brake flange which are displaceable axially only, bolts fixed to one of the two brake discs and between same, stationary stops, an arm and a nose both integral withsaid pawl, said arm adapted to strike against said stops in the two end positions of the pinion shaft thereby turning said nose of the pawl in such ,a position that the brake is opened or closed, a resilient member interposed between said current switch and the pinion shaft, adapted to move the pinion shaft axially.

ALBERT KAUFMANN. 

